High-Sensitivity Dual-Probe Detection of Urinary miR-141 in Cancer Patients via a Modified Screen-Printed Carbon Electrode-Based Electrochemical Biosensor.

The screening and diagnosis of cancer are hallmarks of medicine in the aging population. Recently, microRNAs have shown potential for use as biomarkers, which could advance the field of diagnostics. The presence of miRNA-141 in the serum has been well described in several malignancies. However, the invasive approach used for sampling represents the major limitation for its practical application and, hence, its notable absence as a method for screening the general population. In light of this, we aimed to develop a high-sensitivity microRNA (miR) biosensor for application in the diagnosis of all miR-141-associated cancers, such as colorectal cancer (CRC) and breast cancer (BC). The novelty lies in our dual-probe design, which is reliant on the hybridization of the fluorescein isothiocyanate (FITC) targeting probe onto an existing sample of urinary miR-141 in the first step, followed by complementary binding with a biotinylated probe that has been coated on a modified screen-printed carbon electrode (SPCE). The hybridization of the probe and sensor produces signals via the catalytic reduction of H2O2 at HRP-modified SPCEs in the presence of H2O, which was measured by either cyclic voltammetry or chronoamperometry (CA) currents. In our study, the detection and expression of miR-141 in a cohort of colorectal cancer (n = 6) and breast cancer (n = 4) samples showed that its levels were significantly higher than in a healthy cohort (n = 9) (p < 0.004). Moreover, our miR sensor demonstrated high stability, reliability, and sensitivity (p < 0.0001). This work hopefully provides new information for the detection and monitoring of de novo and existing cancers.

Real-time circulating tumor cells detection via highly sensitive needle-like cytosensor-demonstrated by a blood flow simulation.

The concept of rapid detection of circulating tumor cells (CTCs) has always been the focal point of modern and future medicine. However, the dispersity and rarity of CTCs in the bloodstream makes it hard to detect metastasis. Herein, our newly designed needle-like cytosensor demonstrates that the capture and analysis of CTCs are a much less laborious process and have more potential than ever. Our aim is to detect and capture CTCs directly in the bloodstream without altering the genetic information; further benefit of current cytosensor is allows for the whole circulation of blood to run through the cytosensor, giving a much better sensitivity and chance of detecting CTCs. Our functionalized needle-like cytosensor has been modified with 3-aminopropyltriethoxysilane, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, N-hydroxysuccinimide and conjugated streptavidin to allow the binding of the biotinylated-antibody of epithelial cell adhesion molecules, which captures targeted colon cancer CTC. The capability of our needle-like cytosensor to detect CTCs spanned from 102 to 106 cells/mL. Beyond this, the needle-like cytosensor avoids the distortion of the cell information. In addition, we constructed a blood flow simulation that mimics human circulating system about 10 mL/min speed; by using cyclic voltammetry we could detect significant signals from captured cancer CTCs more than 21 cells/mL without delay; the fluorescence dye detection was further performed for data confirmation. The future of biosensors begins with this, by providing early monitoring quality care in cancer therapy.